This invention relates to the sourcing of electrical energy by compact devices, and more particularly to compact batteries.
Batteries commonly employ oppositely poled electrodes at which oxidation and reduction reactions take place in conjunction with a liquid electrolyte that serves as the medium of transfer of ions between the electrodes. When such electrodes are connected to an external circuit with a load, current flows in the circuit and the load is energized.
Liquid electrolytes, which can be aqueous or non-aqueous, have a number of disadvantages. Care must be exercised in controlling the hydrogen ion concenration (pH) in order to prevent the electrolyte from adversely affecting the electrochemical activity of the associated electrodes. In particular, some electrodes suffer a loss in electrochemical activity when in contact with solutions where the hydrogen ion concentration approaches 7, which is the concentration for a neutral solution which is neither acidic nor alkaline, such as pure water. Unless the hydrogen ion concentration of the electrolyte is maintained well below neutral the electrodes can have their electrochemical activity adversely affected.
Similarly, metallic electrodes, such as those fabricated from zinc, undergo spontaneous dissolution in an acid media. Such electrodes consequently cannot be used despite their desirable properties.
Moreover, the protection of a liquid electrolyte from atmospheric oxidation is difficult. This oxidation causes a loss of electrolytic properties and is one reason for the commonly encountered deterioration of batteries with aging.
In addition, batteries and other electrical storage devices which make use of liquid electrolytes have a corresponding increase in weight and volume due to the natural bulk of fluids.
Accordingly, it is an object of the invention to facilitate the sourcing of electrical energy, and to realize the efficient forms for the generation and storage of energy. A related object is to facilitate efficient energy generation by compact devices.
Another object of the invention is to simultaneously increase the life and reduce the cost of compact energy storage and generation devices. A related object is to overcome the adverse aging phenomenon that is commonly associated with liquid electrolytes.
Still another object of the invention is to limit the criticality associated with the use of liquid electrolytes, particularly in connection with opposite poled electrodes. A related object is to reduce the loss of electrode electrochemical activity by virtue of alterations in the hydrogen ion concentration. Another related object is to achieve electrode use which is not adversely affected by liquid electrolytes.
Yet another object of the invention is to use low cost techniques in the realization of suitable, compact energy generators and storage devices. Another object is to enhance performance of energy storage devices at ambient temperatures.
A further object is to reduce the size of energy storage devices for a prescribed amount of energy storage, while simultaneously prolonging the shelf and work life of the devices. A related object is to provide energy storage devices which are capable of rapid recovery from over-load and short circuit conditions. Another related object is to realize energy storage devices which are not permanently damaged by overload and short circuit conditions.
A still further object of the invention is to facilitate the use of new materials in the realization of energy storage.
Yet another object of the invention is to realize energy storage devices which are rechargeable for extended intervals and not degrade upon successive recharging. A related object is to increase the period of storage activity between required rechargings. Another related object is to increase the number of rechargings that are permitted while continuing to provide suitable service.
A further object of the invention is the fabrication of cheap, light weight and solid state electrochromic devices.